Selective system



March 11, 1930. E. wf NILES 1,749,838

SELECTIVE SYSTEM Filed April 1929 Four Purify Selective Zine Cord Lil/cw! R INVENTOR 1 .1 BY A ATTORNEY Patented Mar. 11, 1930 :UNITED STATES ELIOT W. NILES, OF BLOOMFIELD,

NEVJ JERSEY, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK SELECTIVE SYSTEM Application filed April 24,

This invention relates to selective systems, and more particularly to arrangements for causing the selective operation of electro-" responsive devices such as telephone ringers, relays, or the like, Y

In four-party selective ringing systems employed heretofore, positive and negative polarities of current are supplied to the cord circuit of the telephone system for ringing purposes and these are controlled by keys which are manipulated by the operator in selecting the desired party on the four-party line. The keys supply the positively or negatively polarized current between the tip or ring side of the line and ground, thus operating the particular ringer, relay, or the like, having the corresponding tip and ring connection and polarity.

In the present invention, it is proposed to employ a cord circuit for a telephone system whichdoes not require any keys for ringing purposes. A simple alternating current gen erator is used and its output is polarized by rectifying devices which are directly connected in the circuit of, for example, four jacks associated with the telephone line and which correspond to each of the four parties.

These jacks are, of course, connected to the telephone line and include means for connecting the alternating current generator to the proper side of the telephone line for ringing purposes.

One of the objects of this invention is to associate an alternating current generator with a pair of rectifiers and a pair of oppositely polarized ringers, relays, or the like, so that the generated current may be rectified to operate the proper ringer or relay.

lVhile this invention will be pointed out with particularity in the appended claims, the invention itself, both as to its further objects and features, will be better understood from the detailed description hereinafter following, when read in connection with the accompanying drawing, in which Figure 1 represents an arrangement including a cord circuit and a four-party selective'line, this arrangement disclosing the general features of the invention, and Fig. 2 represents the details of means associated with armatures 1929.. Serial No. 357,753.

AA by which the source of ringing current and source of talking current are switched into the cord circuit as required.

Referring to Fig. 1 of the drawing, the cord circuit is shown at the left terminating in a plug P. This cord circuit includes the familiar repeating coil windings CC and DD and the main battery B A generator which is capable of supplying simple alternating current is designated Gr and this generator may be connected to the tip and ring side of the plug P through armatures AA, which are operated by a relay shown and described in connection with Fig. 2 of the drawing.

The sleeve side of plug P is connected in series with a relay R a battery B and ground. Whenever relay R becomes operated, its armature is attracted, closing the circuit of relay R the current required to operate relay R being derived from battery B Relay R is employed for the purpose of reversing the polarity of battery B whenever relay R becomes energized.

The four-party selective line includes four jacks J J J and J any one of which may be engaged by plug P. Four rectifiers K K K and K. are connected, respectively, to the tip sides of the jacks J J J and J respectively. These rectifiers may be of the dry disk or copper oxide type, of any other type well known in the art. It

' is to be noted that two of these rectifiers, K

and K are tied to one side of the telephone line and that the'other two, K and K.., are tied to the other side of the line. Rectifiers K and K are oppositely directed, and therefore one of these'rectifiers, for example, K, will derive positive pulses of current from impressed alternating current, and the other,

K will derive negative current pulses. Rcctifiers K and K 'are also oppositely direct-ed. rectifier K for example, transmitting positive pulsesof current and rectifier K transmitting negative pulses.

The sleeve sides of jacks J and J 4 include resistances F and F respectively. All of the sleeve sides of the four jacks are connected in multiple and in series with a relay R WVhen plug P engages either jack J or J a substantial or they may be U current will flow from battery B voltage is increased beyondthis value.

through the winding of relay R the sleeve sides of plug P and the particular jack engaged, and through the winding of relay R causing the operation of both relays R 'and' corresponding resistance, either F or F interposed in series with the winding of relays R and R preventing the flow of su y stantial current therethrough, and relay R does not become operated. In that event,.ree lay R is unoperated and battery B is connected to the tip and ring sides ofplug P in opposite polarity. The reason for changing the polarity of battery B in connecting plug 1? with either of jacks J 'or J 3 or with either ofja'cks L or J is to properly pole the current from battery B, with respect to the corresponding rectifier so that said current may traverse that rectifier;

The telephone linemay be bridged by'four telephone subsets of any familiar type. Those designated L L L and L represent the subsets-normally employed in four-party selective systems. Two bells E and E are connected to one side of the line through electrical discharge tubes or devices T and T respectively. Bells E and E are connected to the other side of the line through electrical tubes or devices T and T respectively. Devices T T T and T are pre erably sealed tubes enclosing a rare gas,.such. asneon, each preventing the passage o'f'c'ur rent when its voltage is below a predetermined value,

, Bells E E E and E are connected to the line in the manner shown and described in a patent to Messrs; Norton and May, No. 1,517 ,857, dated December 2, 1924. It is to' be noted that bells E and E are positively poled and'that bells E and 1E. are negatively poled.

An individual line may also be terminated in the tip and ring sides of another jack, if desired. A telephone subset of the type 511- ready considered maybe connected to the individual line and mayinclude a bellsimilar to those already considered hereinabove. This line need not include a rectifier, nor a discharge tube or device and it is not necessary for the bell to be poled.

When ,plugP is inserted'in one ofthe jacks J J J3 or J the corresponding party will be rung selectively. It is to be noted that one of the rectifiersK K K 01' K asso-. ciated with the jack engaged by plug P modifies the current transmittedbyfgenerator G 7 so as to produce a polarized pulse to selectively ring the-bell associated with the particular jack engaged. p

The circuit arrangement shown in Fig.2

and passing current when its.

of the drawing discloses how it, is possible to operate the armatures AAassociated with the generator G- of Fig. 1. The sleeve side or plug P is connected to ground through the windings of relays R and R and a battery B in series relationship. Arelay R 'con trols the motion of the'arniatu-res AA and the winding of this relay is connected in series with abattery B3.- The outer contacts of armatures 7AA areconnectfed to the repeating coil windings CO, the inner contact of the upper armature A is connected to ground, and the inner contact of thelower armature A is connected in series with a -marginal relayR the generator G and ground. The relay R1 controls the arm'atures' which connect the main battery B of Fig. 1 in one polarity or the other. A relay R is shown, and since all 'oii-t-he-relaysof'Fi'g. 2' are normally unoperated, the winding of relay R is shunted by a'circuit which includes the armature of relay R and its contact, and

the armature of relay R and its outer contact.

When plug P engages either of the jacks J gor-l shown connected to the-selective-line of 1', relays B and R becomeoperatedg. current flowing frombattery B through the windings of these relays over thesleeve sides of plug. P and the particularjack engaged, through the windingwotth'e relay R and groundi Upon the-operation "of relay R relay R becomes operated, a" circuit being established which includes battery B the armature and: contact of relay R the winding ct relay R and ground. Upon" the op' eration oft-relay R5, relay R becomes operated, a circuit beingqestablishedwhich in 'c'ludes the armature and contact of relay R the armature and contact of relay R the armatureand outer contact ofre'lay R ,tlie

winding. ofrelay R1, battery B5 and ground.

Upon the op'eration'of relay R the armatures AA; become attracted, the upper'armature A he'coming' grounded and the lower armaturebeing connected to generator G through the winding, of the marginal relay R Thus, the generatorG i's'br'idge'd' across the tipand ring! sides of plug P. I i. jack J i, for example, is the jack. of 1 hereto tore engaged by 'plugiP, then the generator G will supply the current which "traverses rectifier-K and the disch'argerd'evice T so as to ring the bell'E The ringing current of'itself, is insufiicient to operate themarginal 'relay R 'But' when'the signaledparty responds to. the. sounclxoi the bell and removes the receiver from the hook "of'his' sub set', the current" from generator G-wi-H increase to the extent sufficient to-causethe inarginalrelay R tobecome operated. Ac-

cordingly, the armature. of relay R opens its associated contactand current is permit ted to flow through the winding of 'relay. R5,

the circuit now established "including battery B the winding of relay R the winding of relay R the armature and contact of relay R and ground. The shunt circuit around the winding of relay R having been removed from the operation of relay R the armature of relay R becomes attracted and relay R becomes locked, the locking circuit including a battery 13,, the armature and inner contact of relay R the winding of relay R armature and contact of relay R and ground. Inasmuch as batteries B and B are common,

- the closure of the front contact of relay R closes a shunt circuit around the winding of relay R causing it to release, and this in turn disconnects the generator from the cord circuit and reconnects the repeating coil windings CC to the cord circuit. \Vhen the plug P is disconnected from the jack of the selective line, the windings of relays R and R become deenergized and upon release of the armature of relay R the relay R also releases. Moreover, upon the release of the armature of relay R the circuit in series with the winding of relay R is opened and relay R releases its armatures.

It is to be noted that relayR is operated by periodic current and is, moreover, operated only when the periodic current flowing through its winding increases beyond a predetermined value. This relay is set so that the current of generator G, which flows merely through one of the ringers and its associated discharge tube, is insufiicient to cause its operation. However, relay R does hecome operated only when the receiver of one of the subsets is removed from its hook after a ringing signal has been impressed upon the'selective line.

While this invention has been disclosed in certain particular embodiments merely for the purpose of illustration, it will be understood that the general principles of this invention may be applied to other and widely varied organizations without departing from the spirit of the invention the appended claims.

l/Vhat is claimed is:

1. A line for a multi-party telephone system which includes a pair of oppositely polarized relays, a pair of two-electrode discharge devices connected respectively in series relationship with said relays, a pair of dry-disk rectifiers associated with the line and corresponding in polarity respectively and the scope of a with said relays, a source of alternating current, means whereby said source may become rectified by one of the rectifiers to produce positive pulses of current which flow through the corresponding discharge device and relay, and means whereby said source may become rectified by the other of said rectifiers to produce negative pulses of current Which flow through the corresponding discharge device and relay.

2. A telephone signaling system comprising a two-wire line, four two-electrode discharge devices each capable of transmitting current when the impressed voltage exceeds a predetermined value, four ringers, two of which are poled positively and the other two of which are poled negatively, two of said discharge devices and two mutually oppositely poled. ringers being respectively connected in series relationship with each other and with one ofthe wires of the line, the

other two of the discharge devices and the other ;two of the ringers being connected re-- spcctively in series relationship with each other and with the other wire of the line, four rectifiers, two of said rectifiers being associated with each wire of the line, means whereby either of the two rectifiers connected with one of the wires of the line may transmitpositive pulses of current capable of being transmitted by one of the discharge devices to operate its associated ringer, and means whereby either of the two rectifiers connected with one of the wires of the line may transmit negative pulses of current capable of being transmitted by one of the discharge devices to operate its associated ringer.

3. A four-party signaling system comprising a telephone line, four rectifiers, two of which are connected to one side of the line and are oppositely directed and the other two of which are connected to the other side of the line and are also oppositely directed, four polarized ringing devices, one corresponding with each rectifying device, two of the ringing devices associated with each side of the line being oppositely polarized, a source of alternating current, and means whereby said source of alternating current may be connected to one side of the line through either of its associated rectifying devices to operate the corresponding ringing device.

4. A telephone system including a line to which a source of alternating current may be connected, two oppositely directed rectifiers, two oppositely poled ringers, one corresponding to each rectifier, and means for connecting a source of alternating current with each of the rectifiers to operate the corresponding ringer.

5. A line for a telephone system including a source of alternating current, two oppositely directed rectifiers, two oppositely polarized ringers, one corresponding to each rectifier, means for selectively transmitting current of said source through either of the rectifiers to operate its corresponding ringer, a battery, and means for connecting said battery to the line in one direction when one of the ringers becomes operated and for connecting said battery to the line in the opposite direction when the other ringer becomes operated.

6. A multi-party selective system including a telephone line, two rectifiers connected with the line, one poled in one direction and tlm other pvol'ed 'i'n the opp'osit'e 'di-recti 'mn',.asourde 0f 'al trnatirxg cur-rent, "a source of direct current, means for 'c'omreb'tizig the source of alternatingcurrent "to" th' time through either ofthe rectifir5=and means for connecting the source of direct currerit to the line'in one direction when one of the rsoti'fiers'tmnsmits current derived from the alternating current source and 'for connect in'g'. the direct current source in'th'e opposite direction when the other ofth'e 'rectifiers' t-ranmits current derived from the alt'ernat ing current sdu'r-ce. In testimony. whereof, I havesig-Iredl my r name to'thisspecification this 23rd day of Apri l51929l ELIOT W. NILES. 

